1) Field of the Invention
The present invention is directed to electromotive diesel (emd) fuel injectors, and more particularly, to gaskets used in emd fuel injectors.
2) Description of the Prior Art
Emd fuel injectors are used in locomotives to inject diesel fuel for combustion. FIG. 1 shows an emd fuel injector 10 that includes a follower 12, a stop pin 14, a stop pin retainer 16, a stop pin spring 18, a body assembly 20, a plunger assembly 22, a gear 24, a seal ring 26, a gear retainer 28, a guide pin 30, a valve nut 32, a spacer 34, a check valve 36, a check valve cage 38, a chart tip assembly 40, a spring seat valve 42, a spring cage valve 44, a valve spring 46, a spill deflector 48, a locating dowel 50, a body plug 52, a rack assembly 54, a rack 56, a rack pin 58, a filter 60, a filter spring 62, a filter cap or a filter nut 64, a plunger spring 66, a fuel connection 68 and fuel line 69, and a calibrating slide 70. Such an emd fuel injector 10 is well known in the art, such as a fuel injector manufactured by General Motors, as well as described in U.S. Pat. No. 5,328,094, which is hereby incorporated by reference.
As shown in more detail in FIGS. 2 and 4, the filter nut 64 (of which two are provided) defines a filter nut fuel line passageway 72 that is in fluid communication with the fuel line 69, which defines a fuel line passageway 74. The fuel line 69 includes a frustaspherical end or fuel line surface 76 that matingly engages or abuts a frustaspherical-shaped surface or nut surface 78 so that fuel line passageways 72 and 74 are aligned.
Referring to FIG. 3, the frustaspherical end 76 sealingly engages the frustaspherical surface 78 through a support block 80 that abuts a connection portion 81 shown in phantom. The support block 80 defines three holes which receive fuel lines 69 and a stud 82. A stud nut 84 is threadably received by the stud 82 and abuts against a surface of the support block 80 and which, in turn, forces the frustaspherical end 76 against the frustaspherical surface 78, thereby forming a liquid seal.
Referring back to FIG. 2, in operation, fuel passes through the fuel line passageways 72 and 74 as indicated by arrows. Over time, the seal formed by the frustaspherical end 76 abutting the frustaspherical surface 78 may fail due to wear caused by vibration and loosening of the stud nut 84. This causes a fuel line leak. The vibration especially is a problem with breaking the seal because both the filter nut 64 and the frustaspherical end 76 are made of steel.
Therefore, it is an object of the present invention to improve the seal between the frustaspherical end 76 and the filter nut 64.